2023 Volume 33 Issue 3 Pages 135-142
Three strains of lactic acid bacteria designated SKA0020, SKA0021, and SKA0024 were isolated from citrus fruits using soy whey medium prepared from soybeans. The taxonomic characteristics including 16S rRNA gene sequences, G+C content, cellular fatty acid composition, amino acid composition of peptidoglycan, and sugar fermentability of three isolates were investigated. From these data SKA0020 and SKA0021 were tentatively identified as Leuconostoc mesenteroides, and SKA0024 was as Lactiplantibacillus plantarum.
When fermented milk was prepared using the isolates, all fermented milk preparations formed good yogurt curd and the bacterial number in the preparations was reached to about 108/ml. In addition, analysis of the aromatic components of fermented milk identified acetoin, which forms characteristic flavor of dairy product. It was also confirmed that all tested strains including the isolates and the type strains of some species of lactic acid bacteria produce acetoin when sugar was added, although there was some difference of acetoin production between these strains. These results suggested that the newly isolated strains of lactic acid bacteria in this study could be used for the production of fermented milk.
